Boost DC-DC Converter with Self-Regulated Output Voltage and Transient Enhancement for Parallel-String Dimmable LED Driver

• Main Authors: Hsu, Shang- Ru, 許尚儒
• Other Authors: 劉邦榮
• Format: Others
• Online Access: http://ndltd.ncl.edu.tw/handle/2r5842

碩士 === 國立臺北科技大學 === 電機工程研究所 === 104 === This thesis proposes a boost dc-dc converter with self-regulated output voltage (SROV) and transient enhancement (TE) schemes for parallel-string dimmable LED driver. Because the voltages across LED strings are different, the LED driver generates additional power losses and the LED currents are unbalance. The SROV control can make the dc-dc converter offer an appropriate level of output voltage corresponding to the voltage across each LED string. The SROV control can not only decrease the power consumptions of current regulators but also enhance current balance effect. The transient response of the boost converter is slow when the output voltage of the boost converter decreases from high level to low level. Thus, the TE scheme is used to turn on all LED strings to accelerate transient response of the boost converter. The chip is implemented with TSMC 0.35 μm 2P4M CMOS process. The experimental results show the proposed LED driver can supply different output voltage based on the different voltage across the corresponding LED string. The recovery time of the output voltage from high level to low level is 50 μs. Compared with conventional LED driver, the efficiency of the proposed LED driver can be increased 6.66% and the current mismatch rate is only 0.71%.